Using Gnupg to encrypt credit card details

I know it is difficult to answer me when the questions to ask is not even simple. I will explain.

I have a provider where I run PHP. My boss needs to store credit card details in the database. But the English law requires them to be encrypted. I want to use gnupg to encrypt the credit card details.
Then I look on php.net and there is a function (among others) called gnupg_init(). This seems to provide all that I want. But when I use it it cannot find the function.
I also read that the gnupg library is available as a PECL. This PECL stuff is all new to me.
I just do not know what to do?
Do I download the library? I think so. But where do I place it?
Do I upload it next to my php programs on the server?
Do I have to change something in the php.ini file?

Can anybody give me an idea as to what I need to do? It is all a big riddle to me now.
Always keep in mind that I want to achieve the following:
- I receive credit card details automatically in my php program. This already works.
- I now store them in the database (already works) but I would like to encrypt them using gnupg before doing that. I know I need a public key from the person that will eventually decrypt it for this.

I never installed a PECL and I do not know how.
I want to run the gnupg_* functions in PHP.
If I look at phpinfo(), I see no gnupg there.
Does that mean my provider does not offer this?
Or can I install it myself?

I take it that the provider does not like it when several users install this or is this normal behaviour?

If you have the pecl command installed yes. That will download the file then you follow the next steps in the instructions. If you don't have the pecl command installed then install it first. How you install it depends on your OS.

There are 10 kinds of people in the world. Those that understand binary and those that don't.

If you don't own the server or have admin (sudo) privileges then it won't matter as you will not be able to install software anyway. If that is the case then you need to ask your systems admin to install it for you.

If that is not possible then you are going to have your work cut out for you. You will probably have to install GPG in your own workspace, and program your page to encrypt/decrypt the data as necessary with 'system' calls rather than PHP extensions.

There are 10 kinds of people in the world. Those that understand binary and those that don't.